This Amazing Robotic Space Hedgehog Could One Day Explore Martian Moons

When we think of the exploration of planetary bodies such as Mars, the Moon, or even asteroids, we tend to think of four-wheeled rovers such as Curiosity or Opportunity. But such rovers are only of use when there's a decent amount of gravity to play with, something that won't be the case when we want to explore the potentially mineral rich environments of asteroids and small moons. Such a scenario is exactly what pushed researchers from NASA's JPL, Stanford and MIT to start thinking outside of the box, creating a new robotic explorer with an unlikely appearance.

Nicknamed 'Hedgehog', this unassuming cube could actually be the blueprint for low-gravity robotic exploration, and its development team has just successfully completed a new round of testing with remarkably positive results.

"Hedgehog is a different kind of robot that would hop and tumble on the surface instead of rolling on wheels. It is shaped like a cube and can operate no matter which side it lands on," said JPL's Issa Nesnas. "The spikes could also house instruments such as thermal probes to take the temperature of the surface as the robot tumbles."

While testing Hedgehog down here on Earth is useful, the only way to get a good idea of the cubic design's capability in a low-g environment is to actually test it in a low-g environment. Enter NASA's C-9 aircraft, a specially designed jet which allows researchers to carry out testing in a low gravity environment, right here on Earth. In June, researchers took two Hedgehog models for a ride on the C-9 in order to get an idea of how its bizarre hops would fare sans gravity. The tests were carried out on a range of surfaces that were designed to replicate the various environments a robotic Hedgehog may end up visiting. Some were sandy, others were rough and rocky, but all were handled brilliantly by this plucky little robot.

What makes the Hedgehog such an exciting prospect is it's potential maneuverability and speed in a tricky low-g environment. While Curiosity might be trundling along quite nicely on Mars, if it were put on the the Red Planet's moon Phobos, it would have a much harder time. On smaller objects, there just isn't enough gravity for a wheeled rover to gain the traction it needs to move around. To put things in perspective, if you found yourself on Phobos you would weigh less than an apple and you could probably launch yourself off the moon with a decent run and jump, which might sound fun, but is no use when you want to explore in a controlled manner. With its controlled tumbles and lightweight design, Hedgehog is the perfect fit for exploring these smaller space rocks, as Stanford's Marco Pavone explains:

Over the past 10 years or so, there's been increasing interest in exploring small bodies-asteroids, comets, anything that's smaller than a planet. We've spent quite a bit of time with scientists at JPL trying to understand what you need for that. The figures that came back from the scientists were that in general, you want to be controllable within 20 percent: if you want to move to a spot 10 meters away, you should be able to get there within 2 meters. Small bodies have surfaces that are heterogeneous, but within small patches, they're homogenous, so you don't need exact precision, although you need some sort of control. With that in mind, we designed this robot.

That level of control described by Pavone was clear for all to see in this admittedly hilarious simulation of a Hedgehog robot tumbling across the asteroid Itokawa. The footage is sped up, but just look at that bad boy go!

While many roboticists strive to create technologies that look futuristic, Hedgehog is more function over fashion. It's novel design may seem gimmicky, but Pavone confirms that Hedgehog is a no frills robot that his team hopes will get the job done with a minimum of fuss.

Sometimes when you work in robotics, you try to come up with a design that is cool. Here, this design is completely science driven. We tried to design something as simple as possible, given the requirements. But just because it's a simple robot doesn't mean it's an easy robot. Everything about it is complicated. But in our opinion, it's the least complicated way to do the job.

Currently in Phase II of its development process, Hedgehog or something similar to Hedgehog could eventually be sent to one of the small moons or asteroids that exist at our end of the solar system. In order to get there, the cube would be carried by a mothership that would not only release it into its new home, but also stick around to help relay its findings back to Earth.

With this latest round of testing complete, the Hedgehog team feels confident that they could get a mission put together fairly quickly, and while there are a lot of other factors to consider with the launch of such a mission, Pavone says that should an opportunity arise, Hedgehog would be ready.

The general strategy is to make this ready for flight, at least in its most basic configuration, fairly soon, so that whenever a flight opportunity arises, we can raise our hands and say, 'look, we have an option here with a secondary payload to dramatically increase your science with a minimal cost.'